The diagnosis of tuberculosis and other respiratory ailments necessitates the taking of sputum samples for testing and analysis. Such specimens are typically collected by a doctor, nurse or laboratory technician using one of a number of known sputum collection systems.
An important requirement of any sputum collection system is that it minimize the risk of contamination of hospital or lab personnel who handle the device. In an effort to reduce this danger, one device of the prior art employs a graduated cylinder having a funnel attached at one end. A protective outer body encloses the cylinder entirely and attaches to the funnel. The cylinder is mounted within an annular ring on a removable bottom lid of the enclosure. A threaded cap is mounted sideways on the inside wall of the enclosure. After the sputum specimen has been collected the funnel and cylinder are removed from the enclosure and the bottom lid is opened. The open end of the cylinder is inserted into the bottom of the enclosure, and the cylinder is tilted to engage the cap and slide it out of the enclosure and loosely onto the cylinder. The cap is then tightened by hand on the cylinder and centrifuging and testing are performed. The enclosure and funnel are both discarded.
This sputum collection system exhibits a number of disadvantages. For example, it is complex and awkward to use. Because of the sideway position of the cap in the enclosure, it is very difficult to thread the cylinder directly onto the cap while that cap is still in the enclosure. Therefore, the cap must often be slid out of the enclosure and hand-tightened. An extra time-consuming step is thus added and the lab technician's hands are exposed to the risk of inadvertantly contacting the open end of the sputum-containing cylinder. Moreover, sliding the cap out of the receptacle is a very delicate maneuver and it is quite easy for the cap to slip off the cylinder and drop to the floor, where it may be readily contaminated.
The large enclosure presents additional problems. Although the bottom of the enclosure flares slightly, the large longitudinal enclosure still presents a relatively high center of gravity. The device is therefore unstable and tends to tip over when it is transported on a hospital cart, tray or similar apparatus. Furthermore, when the enclosure and funnel are removed the annular ring in the bottom lid is insufficient to independently hold the cylinder upright. The enclosure and funnel are themselves discarded, and in any event it is unsanitary, awkward and wholly impractical to reassemble the enclosure to enable the capped cylinder to stand upright. Therefore, a separate rack is required for storing or transporting the specimen-containing cylinder. Additionally, the size of the enclosure adds to the complexity and costs of manufacturing the device.